[coverattach=1]O’FALLON, MO – The National Guard American Drag Racing League (ADRL) announced today several rule clarifications related to the use of superchargers in its Pro Extreme and Extreme 10.5 classes.

- Use of any size centrifugal, roots-type or screw-type supercharger allowed.
- Maximum overdrive for a roots-type supercharger is 1.70 (70 percent over).
- Maximum overdrive for a PSI screw-type supercharger is 2.28 (128 percent over).
- Maximum overdrive for a Whipple screw-type supercharger is 1.60 (60 percent over).
- All screw-type superchargers must be certified to SFI Spec 34.1 and overdrive limit established to be eligible for ADRL competition.
- Any new screw-type supercharger must be approved for competition prior to competing at an ADRL event.
- All screw-type superchargers must display a current SFI Recertification tag.

“We haven’t had a problem in this area, but these rules are intended to head off any issues before they arise,” National Guard ADRL Executive Vice President of Competition Bubba Corzine explained. “We just want to put it in writing and make sure that all of our race teams know where we stand in regard to these power enhancers.”

ABOUT THE NATIONAL GUARD
The National Guard is the oldest component of the Armed Forces of the United States and one of the nation’s longest enduring institutions. The National Guard operates in all 50 states, three territories (Puerto Rico, Guam and the Virgin Islands) and the District of Columbia. For more information on the National Guard, visit www.NATIONALGUARD.com.

ABOUT THE ADRL
Based in O’Fallon, Missouri, the American Drag Racing League is the nation’s premier sanctioning body for the sport of eighth-mile drag racing. The professional categories featured in the ADRL are Extreme Pro Stock, Pro Extreme Motorcycle, Extreme 10.5, Pro Nitrous, and Pro Extreme, the quickest doorslammer class in all of drag racing. The 2009 National Guard ADRL series consists of 10 national events run throughout the United States. For more information on the ADRL, visit ADRL.us :: Home.